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Restrictive Cardiomyopathy

Updated : May 20, 2024





Background

Restrictive cardiomyopathy (RCM) is a rare form of heart muscle disease characterized by increased stiffness of the myocardium. This increased stiffness impairs the heart’s ability to stretch and fill with blood during the diastolic phase, leading to decreased cardiac output and potential heart failure. Unlike other forms of cardiomyopathy, the contractile function of the heart muscle may be relatively preserved in RCM.

Restrictive cardiomyopathy is characterized by impaired diastolic function in a ventricle that does not undergo dilation. Various restrictive cardiomyopathies exhibit differences in pathogenesis, clinical manifestations, diagnostic assessments, therapeutic approaches, and prognoses. Among the primary etiologies of RCM are cardiac amyloidosis, cardiac hemochromatosis, and cardiac sarcoidosis.

Epidemiology

Restrictive cardiomyopathy is considered rare compared to other forms of cardiomyopathy, such as dilated and hypertrophic cardiomyopathy. Its prevalence is often lower in comparison. While RCM can affect individuals of different age groups, it may be more commonly diagnosed in older adults. However, cases can also occur in children. Cardiac amyloidosis is a significant contributor to RCM.

The prevalence of amyloidosis, in general, can vary, and it may be associated with aging, certain genetic factors, and specific diseases. Cardiac sarcoidosis, another potential cause of RCM, is more prevalent in certain populations. The prevalence of sarcoidosis can be higher in African Americans and individuals from certain regions. The prevalence of RCM and its causes can vary globally. Access to healthcare, genetic factors, and environmental influences may contribute to these variations.

Anatomy

Pathophysiology

The primary hallmark of RCM is increased stiffness of the ventricular walls. This can be attributed to various pathological processes, including fibrosis, infiltration of abnormal substances (e.g., amyloid deposits), or inflammation. In RCM, the stiffened myocardium restricts the ventricles from adequately expanding and accommodating incoming blood. This leads to impaired diastolic function, resulting in decreased ventricular filling.

Compliance refers to the ability of the myocardium to stretch and expand in response to filling pressures. In RCM, reduced compliance means that the ventricles are less able to accommodate normal volumes of blood during diastole. As the ventricles struggle to fill properly, filling pressures within the heart chambers increase. This can lead to congestion in the pulmonary circulation and backward flow of blood into the systemic circulation.

In response to increased ventricular filling pressures, the atria may dilate as they work to compensate for the impaired filling of the ventricles. This dilation can contribute to atrial arrhythmias. In some cases of RCM, there may be excessive fibrous tissue deposition on the endocardium, further contributing to decreased compliance. The heart may attempt to compensate for the impaired diastolic function by increasing heart rate and utilizing atrial contraction to enhance ventricular filling. However, these compensatory mechanisms may not be sufficient in the long term.

Etiology

Cardiac Amyloidosis

Cardiac Sarcoidosis

Endomyocardial Fibrosis

Cardiac Hemochromatosis

Löffler’s Syndrome

Connective Tissue Disorders

Infiltrative Diseases

Radiation Therapy

Certain drugs, such as mercurial agents, anthracycline, ergotamines, busulfan, methysergide.

Genetics

Prognostic Factors

Like other forms of cardiomyopathies, restrictive cardiomyopathy carries an exceptionally poor prognosis, standing out as the cardiomyopathy with the most unfavorable outlook. According to statistical analyses, the reported survival rate spans 2 to 5 years.

Clinical History

RCM typically follows a chronic course, with symptoms progressing slowly over months or years. The underlying causes, such as amyloidosis or sarcoidosis, contribute to the chronic nature of the condition. Patients often present with shortness of breath, particularly during exertion or when lying down. This is due to impaired ventricular filling leading to elevated filling pressures and pulmonary congestion.

Reduced cardiac output can result in generalized fatigue and weakness. Fluid retention may manifest as swelling in the extremities due to impaired circulation. The onset is often insidious, meaning that it develops gradually over time. This can make early detection challenging. In some instances, patients may remain asymptomatic during the early stages of RCM, and symptoms become apparent as the condition advances.

Physical Examination

It is crucial to consider restrictive cardiomyopathy as a potential diagnosis in individuals exhibiting normal or near-normal systolic function, coupled with indications of diastolic dysfunction and a restrictive filling pattern evident on an echocardiogram. Symptomatic presentations of RCM can vary widely, ranging from overt heart failure marked by jugular venous distension, lower extremity edema, ascites and occasionally pulmonary edema, to complaints of diminished exercise tolerance or the identification of new arrhythmias such as atrial fibrillation.

In some distressing instances, patients may present with sudden cardiac arrest. Uncommon presentations encompass scenarios where RCM is mistaken for hypertrophic cardiomyopathy with left ventricular outflow obstruction, or where ischemia, thrombus, and other conditions are involved. During the assessment and physical examination of a patient suspected of having RCM, it is imperative to scrutinize for extracardiac manifestations. For instance, the presence of carpal tunnel syndrome may suggest amyloidosis, while bilateral hilar infiltrates could indicate sarcoidosis.

Hemochromatosis may exhibit classic features such as bronze skin, arthralgias, cirrhosis, and endocrinopathies like diabetes mellitus. The cardiac impulse in RCM is characterized by less displacement than in dilated cardiomyopathy and less dynamism than in hypertrophic cardiomyopathy. In sinus rhythm, a fourth heart sound is more prevalent than a third heart sound, although atrial fibrillation is frequently observed. Jugular venous pressures often exhibit rapid Y descents and may rise during inspiration, a phenomenon known as positive Kussmaul’s sign.

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Differential Diagnoses

Acute Heart Failure

Chronic Heart Failure

Acute Pericarditis

Chronic Pericarditis

Constrictive Pericarditis

Hypertensive Heart Disease

Hypertrophic Cardiomyopathy

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

The treatment of restrictive cardiomyopathy involves addressing both the underlying cause and managing symptoms of heart failure that may arise as a consequence of the disease. While there is currently no cure for RCM, various treatments are available to alleviate its symptoms. To address heart failure symptoms, diuretics are a primary treatment to reduce volume overload. However, careful monitoring is essential to prevent excessive diuresis, given that patients with RCM often rely on elevated filling pressures to maintain cardiac output.

In some cases, beta-blockers or calcium channel blockers may be introduced to increase filling time, potentially aiding in the treatment of dysrhythmias, which are common in this patient population. Angiotensin-receptor blockers may also be considered, particularly if concurrent systolic heart failure develops. For cases associated with sarcoidosis, antiarrhythmics are frequently chosen due to the elevated incidence of conduction disease.

Additionally, immunosuppressive agents such as corticosteroids and steroid-sparing agents may be utilized in the treatment of sarcoidosis. In situations linked to hemochromatosis, therapeutic phlebotomy stands as the treatment of choice. Advanced heart failure interventions, including cardiac transplantation or left ventricular assist devices, may be appropriate for certain patients. The selection of a specific therapy is contingent upon the patient’s clinical condition, the risk of potential adverse events, and the individual’s capacity to tolerate the prescribed treatment.

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Medication

Media Gallary

References

Restrictive Cardiomyopathy

Updated : May 20, 2024




Restrictive cardiomyopathy (RCM) is a rare form of heart muscle disease characterized by increased stiffness of the myocardium. This increased stiffness impairs the heart’s ability to stretch and fill with blood during the diastolic phase, leading to decreased cardiac output and potential heart failure. Unlike other forms of cardiomyopathy, the contractile function of the heart muscle may be relatively preserved in RCM.

Restrictive cardiomyopathy is characterized by impaired diastolic function in a ventricle that does not undergo dilation. Various restrictive cardiomyopathies exhibit differences in pathogenesis, clinical manifestations, diagnostic assessments, therapeutic approaches, and prognoses. Among the primary etiologies of RCM are cardiac amyloidosis, cardiac hemochromatosis, and cardiac sarcoidosis.

Restrictive cardiomyopathy is considered rare compared to other forms of cardiomyopathy, such as dilated and hypertrophic cardiomyopathy. Its prevalence is often lower in comparison. While RCM can affect individuals of different age groups, it may be more commonly diagnosed in older adults. However, cases can also occur in children. Cardiac amyloidosis is a significant contributor to RCM.

The prevalence of amyloidosis, in general, can vary, and it may be associated with aging, certain genetic factors, and specific diseases. Cardiac sarcoidosis, another potential cause of RCM, is more prevalent in certain populations. The prevalence of sarcoidosis can be higher in African Americans and individuals from certain regions. The prevalence of RCM and its causes can vary globally. Access to healthcare, genetic factors, and environmental influences may contribute to these variations.

The primary hallmark of RCM is increased stiffness of the ventricular walls. This can be attributed to various pathological processes, including fibrosis, infiltration of abnormal substances (e.g., amyloid deposits), or inflammation. In RCM, the stiffened myocardium restricts the ventricles from adequately expanding and accommodating incoming blood. This leads to impaired diastolic function, resulting in decreased ventricular filling.

Compliance refers to the ability of the myocardium to stretch and expand in response to filling pressures. In RCM, reduced compliance means that the ventricles are less able to accommodate normal volumes of blood during diastole. As the ventricles struggle to fill properly, filling pressures within the heart chambers increase. This can lead to congestion in the pulmonary circulation and backward flow of blood into the systemic circulation.

In response to increased ventricular filling pressures, the atria may dilate as they work to compensate for the impaired filling of the ventricles. This dilation can contribute to atrial arrhythmias. In some cases of RCM, there may be excessive fibrous tissue deposition on the endocardium, further contributing to decreased compliance. The heart may attempt to compensate for the impaired diastolic function by increasing heart rate and utilizing atrial contraction to enhance ventricular filling. However, these compensatory mechanisms may not be sufficient in the long term.

Cardiac Amyloidosis

Cardiac Sarcoidosis

Endomyocardial Fibrosis

Cardiac Hemochromatosis

Löffler’s Syndrome

Connective Tissue Disorders

Infiltrative Diseases

Radiation Therapy

Certain drugs, such as mercurial agents, anthracycline, ergotamines, busulfan, methysergide.

Like other forms of cardiomyopathies, restrictive cardiomyopathy carries an exceptionally poor prognosis, standing out as the cardiomyopathy with the most unfavorable outlook. According to statistical analyses, the reported survival rate spans 2 to 5 years.

RCM typically follows a chronic course, with symptoms progressing slowly over months or years. The underlying causes, such as amyloidosis or sarcoidosis, contribute to the chronic nature of the condition. Patients often present with shortness of breath, particularly during exertion or when lying down. This is due to impaired ventricular filling leading to elevated filling pressures and pulmonary congestion.

Reduced cardiac output can result in generalized fatigue and weakness. Fluid retention may manifest as swelling in the extremities due to impaired circulation. The onset is often insidious, meaning that it develops gradually over time. This can make early detection challenging. In some instances, patients may remain asymptomatic during the early stages of RCM, and symptoms become apparent as the condition advances.

It is crucial to consider restrictive cardiomyopathy as a potential diagnosis in individuals exhibiting normal or near-normal systolic function, coupled with indications of diastolic dysfunction and a restrictive filling pattern evident on an echocardiogram. Symptomatic presentations of RCM can vary widely, ranging from overt heart failure marked by jugular venous distension, lower extremity edema, ascites and occasionally pulmonary edema, to complaints of diminished exercise tolerance or the identification of new arrhythmias such as atrial fibrillation.

In some distressing instances, patients may present with sudden cardiac arrest. Uncommon presentations encompass scenarios where RCM is mistaken for hypertrophic cardiomyopathy with left ventricular outflow obstruction, or where ischemia, thrombus, and other conditions are involved. During the assessment and physical examination of a patient suspected of having RCM, it is imperative to scrutinize for extracardiac manifestations. For instance, the presence of carpal tunnel syndrome may suggest amyloidosis, while bilateral hilar infiltrates could indicate sarcoidosis.

Hemochromatosis may exhibit classic features such as bronze skin, arthralgias, cirrhosis, and endocrinopathies like diabetes mellitus. The cardiac impulse in RCM is characterized by less displacement than in dilated cardiomyopathy and less dynamism than in hypertrophic cardiomyopathy. In sinus rhythm, a fourth heart sound is more prevalent than a third heart sound, although atrial fibrillation is frequently observed. Jugular venous pressures often exhibit rapid Y descents and may rise during inspiration, a phenomenon known as positive Kussmaul’s sign.

Acute Heart Failure

Chronic Heart Failure

Acute Pericarditis

Chronic Pericarditis

Constrictive Pericarditis

Hypertensive Heart Disease

Hypertrophic Cardiomyopathy

The treatment of restrictive cardiomyopathy involves addressing both the underlying cause and managing symptoms of heart failure that may arise as a consequence of the disease. While there is currently no cure for RCM, various treatments are available to alleviate its symptoms. To address heart failure symptoms, diuretics are a primary treatment to reduce volume overload. However, careful monitoring is essential to prevent excessive diuresis, given that patients with RCM often rely on elevated filling pressures to maintain cardiac output.

In some cases, beta-blockers or calcium channel blockers may be introduced to increase filling time, potentially aiding in the treatment of dysrhythmias, which are common in this patient population. Angiotensin-receptor blockers may also be considered, particularly if concurrent systolic heart failure develops. For cases associated with sarcoidosis, antiarrhythmics are frequently chosen due to the elevated incidence of conduction disease.

Additionally, immunosuppressive agents such as corticosteroids and steroid-sparing agents may be utilized in the treatment of sarcoidosis. In situations linked to hemochromatosis, therapeutic phlebotomy stands as the treatment of choice. Advanced heart failure interventions, including cardiac transplantation or left ventricular assist devices, may be appropriate for certain patients. The selection of a specific therapy is contingent upon the patient’s clinical condition, the risk of potential adverse events, and the individual’s capacity to tolerate the prescribed treatment.

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